In an optical communication system, it is generally necessary to couple an optical fiber to an opto-electronic transmitter, receiver or transceiver device and to, in turn, couple the device to an electronic system such as a switching system or processing system. These connections can be facilitated by modularizing the transceiver device. Such transceiver modules include a housing in which are mounted opto-electronic elements, optical elements, and electronic elements, such as one or more light sources (e.g., lasers), light sensors, lenses and other optics, digital signal driver and receiver circuits, etc. In addition, a transceiver module typically includes an optical connector that can be coupled to a mating connector at the end of a fiber-optic cable. Various transceiver module configurations are known.
Some types of electronic devices can be mounted directly on the surface of a circuit board. Such “surface-mount technology” (SMT) can provide a greater density of electrical contacts between the device and the board than prior technologies. Some surface-mount devices include a rectangular array of electrical contacts on their lower surfaces that can be connected to corresponding electrical contacts on the surface of the circuit board. For example, microprocessors and similarly complex integrated circuit devices typically include such an array of electrical contacts. The array of electrical contacts on the lower surface of such a device can be, for example, of a type known as Ball Grid Array (BGA). A BGA connector comprises a planar array of metallic bumps or balls formed on the lower surface of the connector. A BGA connector can be connected to a circuit board by soldering the bumps to corresponding metallic pads on the surface of the circuit board using surface-mount solder technology. Not only integrated circuit devices but also various types of connectors and adapters can include BGA and similar electrical contact arrays.
While BGA electrical contacts are common, various other types of electrical contact arrays are also known. One family of electrical contact array includes those that have resilient contacts rather than solderable bumps or similar solderable leads. This family of connectors includes a type of connector known as the Landing Grid Array (LGA). An LGA connector comprises an array of resilient contact fingers or spring fingers. A device having an LGA connector can be connected to a circuit board by orienting the device in a position in which the resilient fingers are vertically aligned with corresponding metallic pads on the circuit board surface and then providing a force that resiliently compresses or flexes the fingers against the metallic pads. In a typical LGA, the fingers are very small and flex only a few mils (i.e., thousandths of an inch) or a few tens of mils toward the metallic pads. A retaining mechanism must be employed to maintain the device in this state, i.e., to counteract the spring force and thus maintain good electrical and mechanical contact between the fingers and the pads.